Interpretive Summary: Botryodiplodin is a biological toxin produced by the fungus which causes charcoal rot disease in soybeans and 500 other crop and decorative plants around the world, particularly in times of draught. Charcoal rot disease can cause losses as high as $190 million a year in the US alone. If we could understand how the charcoal rot fungus attacks plants, we might be able to create plants that are resistant to the disease. The fungus is believed to use botryodiplodin when it attacks plants. Botryodiplodin is uniquely similar to ribose, a basic component of all plant, animal and microbial tissues. This article explores the possibility that botryodiplodin may be toxic because of its similarity to ribose, but in the end the conclusion is reached that the toxin works some other way still to be determined.

Technical Abstract:
Many toxins owe their mechanisms of action to being structural analogs of essential metabolites, messengers or structural components. Examples range from tubo-curare to penicillin. Ribose plays a unique role in the metabolism of living organisms, whether prokaryotes or eukaryotes. It and its derivatives are essential components of informational macromolecules (DNA, RNA) and of key components in the energy currency of cells (ATP, GTP). Ribose derivatives play key roles in photosynthesis in green plants. In principle, ribose analogs should constitute excellent toxins. They are simple to make, rapidly diffusible, and may be actively transported into target cells. In principle, they could act as effective anti-metabolites that would be toxic by either (i) inhibiting the enzymes that synthesize essential components of the informational or energy systems of the cell; or (ii) serving as substrates for the same enzymes, which would convert ribose analogs to another set of metabolically non-functional analogs.